In the Star Wars timeline, when does SW:TOR take place?

It is set around 300 years after the events of KOTOR (placed at 3956 BBY), which puts it around 3600 years before the events of the original trilogy. 3653 BBY is the most common date, however the storyline of the game expands both before and after that.

There are books that explain the back story of the game, as well as games. However, obviously these sources don't place themselves in time in relation to events that haven't happened yet.

The assumed oldest character from the movies, I think, is Yoda. He is around 2700 years away from being born at this point in the timeline.